Hi folks New to the forums so forgive me if this is posted in the wrong one. I have an 04 Trailblazer EXT LT 4x4 with the I6 and 177,000 miles. The problem I'm having progressively got worse over a period of a couple days after 2 trips of about 1400 miles total. I noticed at first while accelerating above 40mph that the vehicle didn't seem to have the spunk that it had. Almost seemed as though it was using too high of a gear; kind of like skipping second and going into third. Although the transmission seems fine. A few days after that when I accelerate above 40mph it seems to have a lot of hesitation and takes some time to achieve speed. If i give it more gas it has a growling noise from the engine, especially on hills. While driving i feel intermittent bursts of power. Slight, but noticeable. All is fine while in park or up to 30mph. Idles wonderfully. I replaced the VVT and the camshaft position sensor, also reset the computer for relearn. Still nothing. I had the code P0014, waiting for it to come back on after relearn. I replaced 1 and 5 ignition coils last winter due to a random misfire and cleaned throttle body while replacing them and the plugs. Was fine till now. Also, my Trailblazer conforms to emission standards to be sold in California so please tell me it could be something other than the cat. Appreciate any feedback. Thanks.